Late-life depression and risk of all-cause and cause-specific mortality in an Asian population: the Singapore Chinese Health Study.

INTRODUCTION: Although late-life depressive symptoms were associated with mortality risk, their relationship with cause-specific mortality remained unclear. Hence, we investigated these in older Chinese adults living in Singapore. METHODS: We used data from 16 782 participants aged 61-96 years from follow-up 3 (2014-2016) of the Singapore Chinese Health Study. Depressive symptoms were defined as having ≥5 symptoms on the 15-item Geriatric Depression Scale. Mortality data were obtained through linkage with nation-wide death registry till 31 December 2022. We used Cox proportional hazard models and competing risk regression models to estimate HRs and 95% CIs for association with mortalities. RESULTS: After a mean follow-up of 6.9 years, there were 2 960 deaths. Depressive symptoms were significantly associated with total and cause-specific mortality; the multivariable-adjusted HRs (95% CIs) were 1.20 (1.11 to 1.30), 1.38 (1.14 to 1.67), 1.41 (1.16 to 1.70) and 1.91 (1.13 to 3.21) for mortalities from all causes, ischaemic heart disease (IHD), infectious respiratory diseases and chronic, non-malignant respiratory diseases, respectively. The associations were stronger among smokers for all-cause mortality (HR (95% CI) 1.55 (1.25 to 1.92) vs 1.15 (1.05 to 1.26) in non-smokers; P difference=0.012) and IHD mortality (2.27 (1.33 to 3.90) vs 1.27 (1.03 to 1.57); P difference=0.049) and stronger for IHD mortality among participants aged <75 years (1.89 (1.35 to 2.64) vs 1.16 (0.92 to 1.46) among those aged ≥75 years; P difference=0.019). CONCLUSIONS: Late-life depressive symptoms were associated with increased risk of all-cause, IHD and respiratory disease mortalities. The associations were stronger among those <75 years old and smokers, highlighting the importance of screening for and addressing depressive symptoms in these at-risk groups.